1. Field of the Invention
The present invention relates to an apparatus for separating components of waste or surplus fresh concrete or the like for subsequent recovery and recycling thereof. The concrete is in a mixed, wet, plastic condition, ready for use when put into the novel concrete reclaimer prior to separation, recovery, and recycling.
2. Description of the Prior Art
Apparatus including a rotary screen for separating or components from aggregates or pulps, such as sand and gravel mixtures, concrete mixtures, and ash residues containing larger particles, such as slag and coal, are known. In those instances wherein the solid is substantially homogeneous and mere dewatering is required, gravitational and centrifugal action alone may satisfy the requirement. An example of a rotary screen having open ends and being supported on and driven by rollers is seen in U.S. Pat. No. 4,236,999, issued on Dec. 2, 1980, to George Burgess et al. Because the purpose of this invention is simple dewatering, the substance being treated is introduced into the screen in a trough inside the cylindrical screen extending the entire length therealong. Solids, to the extent that liquids are removed from the original substance, are discharged axially at an open end of the cylindrical screen.
In a closely related invention, seen in U.S. Pat. No. 4,140,629, issued to James H. Martindale on Feb. 20, 1979, material for dewatering is introduced into one open end of a cylindrical screen and migrates toward the other open end. A shower provides water for separation of certain solids from others. Unlike the invention of the present invention, the separator includes radial struts connecting the cylindrical screen to a central support bar, the shower comprises water flowing under influence of gravity from the top of the screen thereinto, and internal baffles are provided to obstruct rapid migration of the initial material through the separator.
Separation into three streams by size is illustrated in U.S. Pat. No. 1,577,136, issued to John Markman on Mar. 16, 1926. A rotary screen has three grades of mesh fineness. The screen is enclosed within a housing having constricted ends, so that loading and discharge through the open ends of the screen are rendered more difficult. No water is employed to facilitate separation.
A rotary screen separator employing water delivered by a pipe extending through and inside the screen is seen in U.S. Pat. No. 1,378,623, issued to Henry J. Schaffer on May 17, 1921. The screen is slightly inclined with respect to the horizontal to facilitate migration of solids therethrough. The water is used to suppress dust, and is discharged "in various directions" (page 2, lines 79-80) from the pipe.
U.S. Pat. No. 1,461,067, issued to Robert W. Moser on Jul. 10, 1923, discloses a sand and gravel washing and sorting apparatus including an inlet chute into which is discharged water. No water is introduced into the sorting screen.
Two patents directed toward separating fresh concrete into its constituent components for disposal of waste concrete and subsequent reclamation of recovered components are seen in U.S. Pat. Nos. 2,983,378 and 4,616,786, issued respectively to Louis G. Hilkemeier on May 9, 1961 and to Rudolf Riker on Oct. 14, 1986. These inventions include screw or baffles facilitating transport of the fresh concrete through the respective apparatus. Both also feature immersion of the concrete or of some residual solids in standing water. Riker provides only immersion contact of solids with water. Hilkemeier sprays a portion of the concrete, and immerses another portion.
At least a portion of the components are conveyed upwardly through the screen, against gravity, in the Hilkemeier device. The Riker apparatus includes a separate receiving bin, requires scooping buckets and an elevator to move separated components upwardly for storage or removal, and has timed spraying cycles.
There remains a need for an uncomplicated, efficient separator for fresh concrete. None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.